The Kofun period (古墳時代,Kofun jidai) is an era in the history of Japan from about 300 to 538 AD, following the Yayoi period. The Kofun and the subsequent Asuka periods are sometimes collectively called the Yamato period. This period is the earliest era of recorded history in Japan, but studies depend heavily on archaeology since the chronology of historical sources tends to be distorted.

It was a period of cultural import. Continuing from the Yayoi period, the Kofun period is characterized by a strong influence from the Korean Peninsula; archaeologists consider it a shared culture across the southern Korean Peninsula, Kyūshū and Honshū.[1] The word kofun is Japanese for the type of burial mound dating from this era, and archaeology indicates that the mound tombs and material culture of the elite were similar throughout the region. From China, Buddhism and the Chinese writing system were introduced near the end of the period. The Kofun period recorded Japan's earliest political centralization, when the Yamato clan rose to power in southwestern Japan, established the Imperial House, and helped control trade routes across the region.[2]

Kofun (from Middle Chinese[citation needed]kú 古 "ancient" + bjun 墳 "burial mound")[3][4] are burial mounds built for members of the ruling class from the 3rd to the 7th centuries in Japan,[5] and the Kofun period takes its name from the distinctive earthen mounds. The mounds contained large stone burial chambers, and some are surrounded by moats.

Kofun come in many shapes, with round and square the most common. A distinct style is keyhole-shaped, with a square front and round back. Kofun range in size from several meters to over 400 meters long, and unglazed pottery figures (Haniwa) were often buried under a kofun's circumference.

The oldest Japanese kofun is reportedly Hokenoyama Kofun in Sakurai, Nara, which dates to the late 3rd century. In the Makimuku district of Sakurai, later keyhole kofuns (Hashihaka Kofun, Shibuya Mukaiyama Kofun) were built during the early 4th century. The keyhole kofun spread from Yamato to Kawachi—with giant kofun, such as Daisenryō Kofun—and then throughout the country (except for the Tōhoku region) during the 5th century. Keyhole kofun disappeared later in the 6th century, probably because of the drastic reformation of the Yamato court; Nihon Shoki records the introduction of Buddhism at this time. The last two great kofun are the 190-metre-long (620 ft) Imashirozuka kofun in Osaka (currently believed by scholars to be the tomb of Emperor Keitai) and the 135-metre long (443 ft) Iwatoyama kofun in Fukuoka, recorded in Fudoki of Chikugo as the tomb of Iwai (political archrival of Emperor Keitai). Kofun burial mounds on the island of Tanegashima and two very old Shinto shrines on the island of Yakushima suggest that these islands were the southern boundary of the Yamato state;[2] it extended north to Tainai in the present-day Niigata Prefecture, where excavated mounds have been associated with a person closely linked to the Yamato kingdom.[6]

Yamato rule is usually believed to have begun about 250 AD, and it is generally agreed that Yamato rulers had keyhole-kofun culture and hegemony in Yamato until the 4th century. Autonomy of local powers remained throughout the period, particularly in Kibi (the present-day Okayama Prefecture), Izumo (current Shimane Prefecture), Koshi (current Fukui and Niigata Prefecture), Kenu (northern Kantō), Chikushi (northern Kyūshū), and Hi (central Kyūshū). During the 6th century, the Yamato clans began to dominate the southern half of Japan. According to the Book of Song, Yamato relationships with China probably began in the late 4th century.

The Yamato polity, which emerged by the late 5th century, was distinguished by powerful clans (豪族, gōzoku). Each clan was headed by a patriarch (氏上, Uji-no-kami), who performed sacred rituals to the clan's kami (objects of worship) to ensure its long-term welfare. Clan members were the aristocracy, and the royal line which controlled the Yamato court was at its zenith. Clan leaders were awarded kabane, inherited titles denoting rank and political standing which replaced family names.

The Kofun period is called the Yamato period by some Western scholars, since this local chieftainship became the imperial dynasty at the end of the period. However, the Yamato clan ruled just one polity among others during the Kofun era. Japanese archaeologists emphasise that other regional chieftainships (such as Kibi) were in close contention for dominance in the first half of the Kofun period; Kibi's Tsukuriyama Kofun is Japan's fourth-largest.

Gilded sword hilts, late Kofun period, 6th century

The Yamato court exercised power over clans in Kyūshū and Honshū, bestowing titles (some hereditary) on clan chieftains. The Yamato name became synonymous with Japan as Yamato rulers suppressed other clans and acquired agricultural land. Based on Chinese models (including the adoption of the Chinese written language), they began to develop a central administration and an imperial court attended by subordinate clan chieftains with no permanent capital. Powerful clans were the Soga, Katsuragi, Heguri and Koze clans in the Yamato and Bizen Provinces and the Kibi clans in the Izumo Province. The Ōtomo and Mononobe clans were military leaders, and the Nakatomi and Inbe clans handled rituals. The Soga clan provided the government's chief minister, the Ōtomo and Mononobe clans provided secondary ministers, and provincial leaders were called kuni no miyatsuko. Craftsmen were organized into guilds.

In addition to archaeological findings indicating a local monarchy in Kibi Province as an important rival, the legend of the 4th-century Prince Yamato Takeru alludes to the borders of the Yamato and battlegrounds in the region; a frontier was near the later Izumo Province (eastern present-day Shimane Prefecture). Another frontier, in Kyūshū, was apparently north of present-day Kumamoto Prefecture. According to the legend, there was an eastern land in Honshū "whose people disobeyed the imperial court" and against whom Yamato Takeru was sent to fight.[citation needed] It is unclear if the rival country was near the Yamato nucleus or further away. The modern-day Kai Province is mentioned as a location where prince Yamato Takeru traveled on his military expedition.

The period's northern frontier was explained in Kojiki as the legend of Shido Shōgun's (四道将軍, "Shōguns to four ways") expedition. One of four shōguns, Ōbiko set out northward to Koshi and his son Take Nunakawawake left for the eastern states. The father moved east from northern Koshi, and the son moved north;[contradictory] they met at Aizu, in present-day western Fukushima Prefecture. Although the legend is probably not factual, Aizu is near southern Tōhoku (the northern extent of late-4th-century keyhole-kofun culture).

During the Kofun period, an aristocratic society with militaristic rulers developed. The period was a critical stage in Japan's evolution into a cohesive, recognized state. The society was most developed in the Kinai region and the eastern Setouchi Region. Japan's rulers petitioned the Chinese court for confirmation of royal titles.

While the rulers' title was officially "King", they called themselves "Ōkimi" (大王, "Great King") during this period. Inscriptions on two swords (the Inariyama and Eta Funayama Swords) read Amenoshita Shiroshimesu (治天下; "ruling Heaven and Earth") and Ōkimi, indicating that the rulers invoked the Mandate of Heaven. The title Amenoshita Shiroshimesu Ōkimi was used until the 7th century, when it was replaced by Tennō.

Many of the clans and local chieftains who made up the Yamato polity claimed descent from the imperial family or kami. Archaeological evidence for the clans is found on the Inariyama Sword, on which the bearer recorded the names of his ancestors to claim descent from Ōbiko (大彦, recorded in the Nihon Shoki as a son of Emperor Kōgen). A number of clans claimed origin in China or the Korean Peninsula.

During the 5th century, the Katsuragi clan (葛城氏, descended from the legendary grandson of Emperor Kōgen) was the most prominent power in the court and intermarried with the imperial family. After the clan declined, late in the century, it was replaced by the Ōtomo clan. When Emperor Buretsu died with no apparent heir, Ōtomo no Kanamura recommended Emperor Keitai (a distant imperial relative in Koshi Province) as the new monarch. Kanamura resigned due to the failure of his diplomatic policies, and the court was controlled by the Mononobe and Soga clans at the beginning of the Asuka period.

Detail of chariots on a Chinese bronze mirror sent to Japan during the Kofun period. From the Eta-Funayama Tumulus, Kumamoto (Tokyo National Museum)

Toraijin refers to people who came to Japan from abroad, including mainland Chinese who inhabited ancient Japan via the Ryukyu Islands or the Korean Peninsula. They introduced numerous, significant aspects of Chinese culture to Japan. Valuing Chinese knowledge and culture, the Yamato government gave preferential treatment to toraijin..[7] According to the 815 book, Shinsen Shōjiroku, 317 of 1,182 clans in the Kinai region of Honshū were considered to have foreign ancestry. One hundred sixty-three were from China, 104 from Baekje ("Paekche" in the older romanization), 41 from Goguryeo, six from Silla, and three from Gaya.[8] They may have immigrated to Japan between 356 and 645.

According to the Shinsen Shōjiroku (used as a directory of aristocrats), Chinese immigrants had considerable influence.[8]. The Yamato imperial court edited the directory in 815, listing 163 Chinese clans.

According to Nihon Shoki, the Hata clan (descendants of Qin Shi Huang)[9] arrived in Yamato in 403 (the fourteenth year of Ōjin) as the vanguard of 120 provinces. According to the Shinsen Shōjiroku, the Hata clan were dispersed throughout a number of provinces during the reign of Emperor Nintoku and forced to practice sericulture and silk manufacturing for the court. When the finance ministry was set up in the Yamato court, Hata no Otsuchichi became chief of several departments (伴造; Tomo no miyatsuko [ja]) and was appointed Ministry of the Treasury (大蔵省; Okura no jo); the heads of the family were apparently financial officials of the court.

In 409 (the twentieth year of Ōjin), Achi no omi (阿知使主)—ancestor of the Yamato-Aya clan [ja], which was also composed of Chinese immigrants—arrived with immigrants from 17 districts. According to the Shinsen Shōjiroku, Achi received permission to establish the province of Imaki. The Kawachi-no-Fumi clan, descendants of Gaozu of Han, introduced elements of Chinese writing to the Yamato court.

Some of the many Korean immigrants who settled in Japan beginning in the 4th century were the progenitors of Japanese clans. According to Kojiki and Nihon Shoki, the oldest record of a Silla immigrant is Amenohiboko: a legendary prince of Silla who settled in Japan at the era of Emperor Suinin, possibly during the 3rd or 4th centuries.

Baekje and Silla sent their princes as hostages to the Yamato court in exchange for military support.[11][12][13][14] King Muryeong of Baekje was born in Kyushu (筑紫) of Japan as the child of a hostage in 462,[15] and left a son in Japan who was an ancestor of the minor-noble Yamato no Fubito (和史,"Scribes of Yamato") clan. According to the Shoku Nihongi (続日本紀), Yamato no Fubito's relative (Takano no Niigasa) was a 10th-generation descendant of King Muryeong of Baekje who was chosen as a concubine for Emperor Kōnin and was the mother of Emperor Kanmu. In 2001, Emperor Akihito confirmed his ancient royal Korean heritage through Emperor Kanmu.[16]

Chinese, Japanese, and Koreans wrote historical accounts primarily in Chinese characters, making original pronunciation difficult to trace. Although writing was largely unknown to the indigenous Japanese of the period, the literary skills of foreigners seem to have been increasingly appreciated by the Japanese elite. The Inariyama Sword, tentatively dated to 471 or 531, contains Chinese-character inscriptions in a style used in China at the time.[17]

The cavalry wore armour, carried swords and other weapons, and used advanced military methods similar to those of Northeast Asia. Evidence of the advances is seen in haniwa (埴輪, "clay ring"), clay offerings placed in a ring on and around the tomb mounds of the ruling elite. The most important of these haniwa were found in southern Honshū (especially the Kinai region around Nara Prefecture) and northern Kyūshū. Haniwa grave offerings were sculpted as horses, chickens, birds, fans, fish, houses, weapons, shields, sunshades, pillows, and male and female humans. Another funerary piece, the magatama (勾玉, "curved jewel"), became symbolic of imperial power.

Much of the material culture of the Kofun period demonstrates that Japan was in close political and economic contact with continental Asia (especially with the southern dynasties of China) via the Korean Peninsula; bronze mirrors cast from the same mould have been found on both sides of the Tsushima Strait. Irrigation, sericulture, and weaving were brought to Japan by Chinese immigrants, who are mentioned in ancient Japanese histories; the Chinese Hata clan (秦, read "Qín" in Chinese) introduced sericulture and certain types of weaving.[18]

The introduction of Buddhism in 538 marked the transition from the Kofun to the Asuka period, which coincided with the reunification of China under the Sui dynasty later in the century. Japan became deeply influenced by Chinese culture, adding a cultural context to the religious distinction between the periods.

The first joint history project between Japan and South Korea was halted in 2005 due to disagreements between the two countries,[33] but was later resumed.[34] The archaeological record and ancient Chinese sources indicate that the tribes and chiefdoms of Japan did not begin to coalesce into states until 300 AD, when large tombs began to appear. Some describe the "mysterious century" as a time of internecine warfare, as chiefdoms competed for hegemony on Kyūshū and Honshū.[35] The Nihon Shoki refers to a Japanese king who is also the Korean sovereign.[36][37][38]

According to historical records in Japan (Nihon Shoki) and Korea (Samguk Sagi), Korean princes were sent to Japan as hostages[37] and Japan founded Silla.[39] In Japan the hostage interpretation is dominant. Jonathan W. Best, who helped translate the remnant of the Baekjae annals,[40] noted that the king of Silla was subordinate to the Japanese emperor.[41]

Archaeological evidence exists of Korean travel to Japan at this time. According to the books Korea and Japan in East Asian History[42] and Paekche of Korea and the Origin of Yamato Japan,[43] horse sculptures, shinju-kyo, painting and ironware made in Northern Wei China do not match the dates of Emperor Ojin's reign.[44]

According to Paekchae of Korea and the origin of Yamato Japan, "The prince of Silla was the ancestor to the Japanese Emperor." The translation of "Nihon Shoki Vol.6" was added and Amenohiboko is described in Nihon Shoki as a maternal predecessor of Empress Jingū[citation needed], whose controversial legend says that she defeated Silla in the 5th Century. This is highly inconsistent, as Jingū is said to have lived in the 2nd and 3rd centuries, and she is supposed to have died in 269 AD which would make her 300 to 400 years old. This conflicting information makes it difficult to understand these records. "天日槍對曰 僕新羅國主之子也 然聞日本國有聖皇 則以己國授弟知古而化歸之" Amehiboko was said to have stated 2 possible translations depending on how you punctuate the sentence and how you evaluate the syntax. 1. "I am a prince in Korea. I heard that there was saint's king in Japan. To become a vassal of the king in Japan, I transferred the country to younger brother." Again in the past the original text and not modern Japanese or Korean translations, lacking past tense/present tense and words like transferring or transferred or transfer would be impossible to interpret. This same sentence can be 2. "I am a prince in Korea. I heard that there was a saint's King in Japan to become a vassal. The king in Japan I transfer the country to my younger brother." It is impossible to tell whether the sentence is stating that a Korean prince loves his younger brother, calling him a saint and ordaining his younger brother to be his vassal (and to rule as the King of Japan), or simply the other way around.

According to the Book of Song, a Chinese emperor appointed five kings of Wa to the position of ruler of Silla in 421,[45] but what is confusing is that Japan wielded influence over the southern part of the Korean peninsula through the remote region according to the Nihon Shoki.[46] In addition, the book of Song and the book of Sui can not be possible because many of the states considered to be Japan's vassal such as Chinhan and Mahan did not exist in the same time period as the vassal king of Yamato. In addition, the Book of Song was incomplete with missing volumes and filled in centuries later in a biased manner for political reasons. Also, Silla did not have official contact with the Song/Sui until the 6th century making this 4th to 5th century statement impossible. "As Egami (1964) notes, it may look very strange that the names of six or seven states listed in the self-claimed titles included Chin-han and Ma-han which had preceded, respectively, the states of Silla and Paekche. Perhaps the King of Wa had included the names of six or seven south Korean states in his title merely to boast of the extent of his rule. But Wa Kings could not have included the names of nonexistent states." Other historians[who?] also dispute Japan's theory, claiming there is no evidence of Japanese rule in Gaya or any other part of Korea.[47][48][citation not found] Another problem with the book of Song and book of Sui is that many of the volumes of the books were missing and re-written later in a biased manner. It is difficult to make any sense of what the relationship was like in the past.

The special burial customs of the Goguryeo culture had an important influence on other cultures in Japan.[51] Decorated tombs and painted tumuli which date from the fifth century and later found in Japan are generally accepted as Northeast of China and Northern part of Korean peninsula exports to Japan.[52] The Takamatsuzuka Tomb even has paintings of a woman dressed in distinctive clothes, similar to wall paintings from Goguryeo and Tang-dynasty China.[53][54] In addition, Chinese astrology was being introduced during this time.

According to the Book of Song, of the Liu Song dynasty, the Emperor of China bestowed military sovereignty over Silla, Imna, Gaya, Chinhan, and Mahan on King Sai of Wa. However, this theory is widely rejected even in Japan as there is no evidence of Japanese rule in Gaya or any other part of Korea.[47][48] After the death of King Kō of Wa, his younger brother Bu acceded to the throne; King Bu requested to have Baekje added to the list of protectorates included in the official title bestowed upon the King of Wa by mandate of the Emperor of China, but his title was only renewed as "Supervisor of All Military Affairs of the Six Countries of Wa, Silla, Imna, Gara, Chinhan, and Mahan, Great General Who Keeps Peace in the East, King of the Country of Wa."[20] This entire statement is impossible because Chinhan and Mahan did not exist in the same time period as Silla, Baekje when the vassal Kings of Yamato were supposed to rule. As Egami wrote in 1964 "But Wa Kings could not have included the names of nonexistent states." In addition, Silla did not have official contact with the Song/Sui until the 6th century making this 4th to 5th century claim not possible. Due to the lack of evidence, and the confusion of whether the Wa were the descendants of Koreans, again no certain information is discernible.

Chinese chronicles note that horses were absent from the islands of Japan; they are first noted in the chronicles during the reign of Nintoku, most likely imported by Chinese and Korean immigrants.[36][37] According to some accounts, the horse was one of the treasures presented when the king of Silla surrendered to Empress Jingū in the Nihon Shoki.[55] Other accounts contend that there is no evidence of this from Silla, and the king who supposedly surrendered dates to the 5th century, thus making Empress Jingū 200 years old. The Nihon Shoki states that the father of Empress Jingū was Emperor Kaika's grandchild, and her mother was from the Katsuragi clan.[56] In addition, the Nihon Shoki states that a Korean from Silla, Amenohiboko, was an ancestor of Jingū so both the Nihon Shoki and the Chinese chronicles relating to Japan are difficult to interpret. In addition, there is no evidence of Japanese war with Korea or any Japanese presence in Korea at this time[47][48] and the Japanese did not have actual knowledge about horses until well after this time.[47][48]

Japan stopped foreign archaeologists from studying the Gosashi tomb, reportedly the resting place of Emperor Jingū, in 1976. In 2008, Japan allowed limited access to foreign archaeologists. According to National Geographic News Japan "has kept access to the tombs restricted, prompting rumors that officials fear excavation would reveal bloodline links between the 'pure' imperial family and Korea—or that some tombs hold no royal remains at all."[57]

The Yamato court had ties to the Gaya confederacy (Japanese: Mimana), and this region of the Korean Peninsula has burial mounds similar to kofun. This has caused scholars to begin examining the relationship between the Yamato and Baekje during the 3rd and 7th centuries (including tomb-construction methods), a variety of theories exist, most have concluded that bi-directional sharing of culture and construction methods existed.[58] Earrings discovered in Silla and Kaya tombs are similar to Japanese earrings dating to the Kofun period: "The ultimate source of such elaborate techniques as granulation is probably the Greek and Etruscan goldsmiths of western Asia and Europe, whose skills were transmitted to northern China and later to Korea. The resemblance of earrings found in Japan in the Kofun period (ca. 3rd century—538 A.D.) to those from Silla and Kaya tombs suggests that such articles are imported from Korea."[59] Tombs in southern Korea and Japan appear to be related,[58] and all kofun-style tombs discovered in Korea have been dated as younger than those in Japan; advanced artifacts found in Korea's tombs are Japanese Haniwa,[60] horse sculptures and earrings.[57][61][62][63][64][65]

Japan and South Korea have agreed in a joint history project that Japan's interpretation of the 4th century was incorrect, but the Japanese government disagreed with the historians.[34] "After conducting research for three years since 2002, scholars of the two countries announced their first report on three categories - the ancient, medieval, and modern times. At that time, Seoul demanded that the research institute’s findings be reflected in the textbooks of the two nations, but Japan rejected this request".[33]

^Brown, Delmer M. (1993). The Cambridge History of Japan: Ancient Japan. Cambridge University Press. p. 141. ISBN0-521-22352-0. Faced with this comeback by Koguryo, Paekche leaders turned to Yamato for military support, even sending its crown prince to Yamato as a hostage in 397 - just as Silla had dispatched princely hostage to Koguryo in 392 when that kingdom was in dire need of military support.

^Pratt, Keith (2007). Everlasting Flower: A History of Korea. Reaktion Books. p. 42. ISBN1-86189-335-3. We can only guess, for example, what it felt like for the girls periodically sent as brides to foreign courts, for the crown prince of Paekche when he was dispatched to the Yamato court as a hostage in AD 397, or for a Silla prince who experienced the same fate in 402.

^The New Encyclopædia Britannica. Encyclopædia Britannica. 2003. p. 279. ISBN0-85229-961-3. Paekche was frequently attacked by Koguryo during the century, prompting continued requests for assistance from Yamato; it is recorded that Paekche even sent a crown prince to Yamato as a hostage on one occasion and the mother of the king on another. Yet, probably because of internal dissension, Yamato did not dispatch any troops to the peninsula. Yamato's interest in Korea was apparently a desire for access to improved continental technology and resources, especially iron.

^Henthorn, William E. (1971). A history of Korea. Free Press. p. 37. In 402, Silla concluded a peace with the Wa. Prince Misahun was then sent to Japan as a hostage. This may have been an act of revenge by the Silla monarch, who, as Prince Silsong, had been sent as hostage to Koguryo by Prince Misahun's father. Despite the peace, Silla-Wa relations were never friendly, due no doubt in part to the Wa-Kaya alliance.

^国語大辞典 (Kokugo Dai Jiten Dictionary) (in Japanese) (新装版 (Revised Edition) ed.), Tokyo: Shogakukan, 1988, 姓氏。古代の有力帰化系氏族。出自は諸説あるが、おそらく五世紀に渡来した中国人の子孫で、養蚕・機織の技術をもって朝廷に仕え、伴造（とものみやつこ）の一員として秦造（はたのみやつこ）を称したと思われる。 Surname. Influential immigrant clan in ancient times. Various theories about origins, but most likely descendants of Chinese immigrants who came to Japan in the fifth century, who are thought to have brought sericulture and weaving technologies and served in the imperial court, and to have been granted the title Hata no Miyatsuko as members of the Tomo no Miyatsuko [an imperial rank responsible for overseeing technically skilled artisans].

^Chinese History Record Book of Sui, Vol. 81, Liezhuan 46 : 隋書 東夷伝 第81巻列伝46 : 新羅、百濟皆以倭為大國，多珍物，並敬仰之，恆通使往來 "Silla and Baekje both take Wa to be a great country, with many rare and precious things; also [Silla and Baekje] respect and look up to them, and regularly send embassies there." [1]"Archived copy". Archived from the original on 2004-12-21. Retrieved 2006-04-29.CS1 maint: Archived copy as title (link)

^ abChinese History Record Book of Song : 宋書 列傳第五十七 夷蠻 : 詔除武使持節、都督倭新羅任那加羅秦韓慕韓六國諸軍事、安東大將軍、倭王。興死，弟武立，自稱使持節、都督倭百濟新羅任那加羅秦韓慕韓七國諸軍事、安東大將軍、倭國王 [2][3]

^Best JW 2007 A History of the Early Korean Kingdom of Paekche, together with an annotated translation of The Paekche Annals of the Samguk sagi (Harvard East Asian Monographs) Massachusetts, Harvard University, Asia studies

^"Complex of Koguryo Tombs". UNESCO World Heritage Centre. Retrieved 2006-05-31. "totalling about 30 individual graves, from the later period of the Koguryo Kingdom, one of the strongest kingdoms in north-eastern China and half of the Korean peninsula between the 3rd century BC and 7th century AD."